freesabaiHash generator: MD5, SHA-256 and HMAC
Compute the MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes of a text or a file, with HMAC if you give a key, and paste the checksum a publisher gives to check that the file you downloaded matches. Files are not uploaded, and files of several GB work without filling your memory.
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How to use it
- Choose "Text" and type or paste, or choose "A file" and pick one. The hash of every algorithm you ticked appears at once (a big file shows a progress bar).
- For HMAC tick "Use HMAC" and give a key. Choose the output as lower-case hex, upper-case hex or Base64.
- To check a download, paste the checksum the source gives into "Check against a given checksum". The tool tells you whether it matches, and which algorithm it matches.
Frequently asked questions
How do I check that a download is not damaged or tampered with?
The site you downloaded from usually gives the SHA-256 (or MD5) of the file. Choose "A file", pick the downloaded file, and paste that value into "Check against a given checksum". If it says "Match ✓" the file is identical to the original, byte for byte. You can paste the whole line from sha256sum: the tool finds the hash in it.
Can it hash a file of several GB?
Yes. The file is read 1 MB at a time and never held whole in memory. There is a progress bar and a Stop button. Speed depends on your computer (usually tens to a hundred MB per second per algorithm). Ticking only the algorithms you need makes it faster.
Are MD5 and SHA-1 still fine to use?
For checking that a file is not damaged, yes, but they are not safe against forgery, because two different inputs with the same hash can be made, and they must never be used to store passwords. For security use SHA-256 or better, and store passwords with a purpose-made algorithm such as bcrypt or Argon2.
Good to know
- Text is turned into UTF-8 before hashing, so Thai gets the same hash as other tools that use UTF-8 (such as
sha256sum). - HMAC is a hash mixed with a secret key; it shows that a message came from someone who knows the key and was not changed. The key can be given as text, hex or Base64.
- The algorithms are written in this page and checked against the standard test vectors (FIPS 180, RFC 1321, RFC 4231) each time the code changes.
Your data stays on your device
Everything runs in your browser. What you type, paste or open is not sent to freesabai's servers or anyone else's, and is not kept in the browser: close the page and it is gone. The site only counts how many times this page was opened and how many times someone copied or saved a result (never what was pasted or the result, and you can switch the counting off in the footer; see the privacy policy).
Report a problem or suggest an idea
Found a bug, or want this tool to do more? Tell us on the feedback page. No sign-up.
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